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Port 3122 (vtr-emulator)

IANA assigns port 3122 to vtr-emulator: MTI VTR Emulator port.

Registered (user) port, 1024-49151 TCPUDP

IANA assignment

Service nameProtoDescriptionAssigneeReference
vtr-emulator TCP MTI VTR Emulator port John Mertus -
vtr-emulator UDP MTI VTR Emulator port John Mertus -

Check what is listening on port 3122

Linux: is anything listening on TCP 3122?
sudo ss -tlnp 'sport = :3122'
Linux: UDP 3122
sudo ss -ulnp 'sport = :3122'
Linux / macOS: which process owns the port
sudo lsof -nP -i :3122
Older Linux / BSD (net-tools)
sudo netstat -tlnp | grep ':3122 '
Windows (Command Prompt)
netstat -ano | findstr :3122
Windows (PowerShell)
Get-NetTCPConnection -LocalPort 3122 -State Listen | Select LocalAddress,OwningProcess

Test it from outside

From another machine
nc -vz -w 5 HOST 3122
From Windows
Test-NetConnection HOST -Port 3122
UDP probe (no reply does not prove it is closed)
nc -vzu -w 5 HOST 3122

Block port 3122 in the firewall

ufw
sudo ufw deny 3122/tcp
iptables
sudo iptables -A INPUT -p tcp --dport 3122 -j DROP
nftables
sudo nft add rule inet filter input tcp dport 3122 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block TCP 3122' -Direction Inbound -Protocol TCP -LocalPort 3122 -Action Block
ufw
sudo ufw deny 3122/udp
iptables
sudo iptables -A INPUT -p udp --dport 3122 -j DROP
nftables
sudo nft add rule inet filter input udp dport 3122 drop
Windows Firewall
New-NetFirewallRule -DisplayName 'Block UDP 3122' -Direction Inbound -Protocol UDP -LocalPort 3122 -Action Block

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All port numbers · Open port checker
Assignment data: IANA port number registry (public domain), retrieved 2026-11-10.